I don't know, I find Shadowheart quite pleasant to have around. She was never bitchy to me. maybe, when you ask her too soon about her background, but that was not offputting to me. The only companion, I find objectively annoying, is Astarion. I hate his voice, demeanor, everything. In my later playthroughs, I often killed him (if he managed to take me down) or just leave him (if my rolls succeed and he just showed the knife).
Lae'zel is to me the most straight forward companion: She has a mission - get rid of the tadpole, before it changes her - and she sticks to it. I can get behind it. As for the rest: Githyanki are not nice, theyare a harsh society and she acts accordingly. Wether she will learn to respect Tav later on and changes her attitude remains to be seen - it would be similar to Sten from Dragon Age Origins, who was similar off putting and irritating in the beginning, but can warm up to the Warden based on their actions. He came from a similar strict and unforgiving society as Lae'zel.
As for Gale and Wyll - they are easy enough to keep around. Do good deeds and they are mostly happy.
What I would critize about the companions is, that they are all so very special. Everyone but Lae'zel has more drama and secrets going on than a whole DnD group. I find it a bit over the top tbh.
Only party member I won't get used to is Wyll. He will never stop being a vampire no matter what. He might be turned into a good aligned vampire if the story takes me in that direction, but a good vampire is perhaps even more pitifull as an evil one, so...
You mean Astarion?
